Reading: RR&K, Chapters 5 and 9
SLIDE 01a mesentery, rat (whole-mount, Verhoeff, orange G, safranin)
(RR&K p103, Fig. 5.8)
For this preparation, small pieces of rat mesentery were excised, spread using needles on a glass slide, and immersed in fixative. These whole-mount preparations were then stained with Verhoeff's hematoxylin for nuclei and elastic fibers, with safranin for mast cell granules, and with orange G for other proteins (mainly collagen). At low power, observe the elastic fibers (thin, dark, sharply defined, frequently branching) and collagen fibers (thick bands of orange stained material, branching only rarely, overlapping, and following a wavy course). Try to identify the following cells: fibroblasts with smal and dense nuclei; mast cells (cytoplasm filled with bright reddish granules) and endothelial cells (lining the blood vessels). Since mast cells are disrupted easily upon injury, you may also see clumps of mast cell granules floating freely within the tissue.
Check list for SLIDE 01a:
SLIDE 42c skin, fingertip (H&E)
(RR&K p392, Fig.1,3; p371, Fig 14.2; p128, Fig. 6.2; p127 Fig. 6.1)
This slide exhibits loose connective tissue, dense irregular connective tissue, and adipose tissue. Refer to your atlas for orientation. Classify the epithelium at the surface. The area immediately beneath the epithelium exhibits a relatively high concentration of nuclei and a low abundance of extracellular matrix. This is loose connective tissue. Deep to the loose connective tissue is a region with fewer nuclei and more extracellular components that stain with eosin. This area represents dense connective tissue. The majority of cells in this tissue are fibroblasts. A majority of the cytoplasm of the fibroblast is distributed amongst numerous pale-staining processing intertwined with the collagen fibers. Therefore, only the elongated nuclei are visible. Study the pattern of collagen fibers in dense irregular connective tissue and the cell types present in both types of connective tissue. Locate regions of adipose tissue and identify adipocytes.
Check list for SLIDE 42c:
SLIDE42d skin, fingertip, (Verhoeff, metanil yellow)
(RR&K p35, Fig.3; p371, Fig 14.2)
Study the organization and distribution of elastic fibers stained dark purple in the regions of loose and dense irregular connective tissue and adipose tissue identified on SLIDE 42c. Where else on this slide can you find well-organized elastic fibers?
Check list for SLIDE 42d:
SLIDE42b skin, fingertip (Masson)
(RR&K p32, Fig.1,3; p371, Fig 14.2)
This section was taken from the same tissue block as SLIDE 42c & SLIDE 42d. Study the organization and distribution of collagen fibers stained dark green in the regions of loose and dense irregular connective tissue and adipose tissue identified on SLIDE 42c.
Check list for SLIDE 42b:
FIGURE 02 Uterus, fibroblast (EM)
(RR&K p121, Fig.1,2,3)
This figure represents a region of loose connective tissue in the uterus. This cell is a fibroblast surrounded by an amorphous extracellular matrix. The fibroblast is an elongated cell sometimes containing processes extending well into the matrix. Such cellular processes can be seen distributed around this fibroblast. The nucleus is usually set to one end of the fibroblast while the other end contains the machinery of protein synthesis. The well-developed Golgi apparatus and dilated rough endoplasmic reticulum suggests that this cell is actively synthesizing proteins such a collagen. A cove, where the extracellular processing events of collagen occurs, can be seen. Mitochondria are evident and dense organelles found in an adjacent process are good examples of lysosomes. This particular fibroblast also has a single cilium with a basal body.
Check list for FIGURE 02:
SLIDE 26a tendon (H&E)
(RR&K p123, Fig.1,2,3)
Examine the arrangement of collagen and fibroblasts in the tendon in this longitudinal section. What similarities and differences do you see between tendon and the dense irregular connective tissue seen in the skin (SLIDE 42c)? Nuclei of the tendinocytes appear as elongated profiles arranged in linear pattern. The cytoplasm is invisible and blends with collagen. The tendon is surrounded by the connective tissue capsule, the epitendineum (which may not be present). Observe subdivisions within the tendon into fascicles, which are separated between themselves by an endotendineum (extension of epitendineum).
Check list for SLIDE 26a: 
1. What criteria are used to classify different connective tissues?
2. Discuss the relationship between the function of different connective tissues and their structure.
3. Describe the fibrous and nonfibrous elements of connective tissue.
4. Explain the striated appearance of collagen visualized in the EM.
5. Which cellular organelles participate in the synthesis of collagen?
6. Describe the relationship of collagen fibrils to collagen fibers.
7. What stains would you use to visualize the distribution of collagen fibers, reticular fibers and elastic fibers in organs?
8. What are the major differences between collagen fibers, reticular fibers, and elastic fibers?
9. Name the major glycosaminoglycans found in ground substance. What physical properties do they confer on connective tissue?
Connective tissue consists of cells and their surrounding matrix. Loose and dense connective tissue, adipose tissue, bone, blood, cartilage, and lymphatic tissue all fall into this category. This unit examines aspects of some forms of connective tissue